The feature will be supported on the latest Pixel 8 series. However, it seems the recently released Pixel 8a won’t be supporting it, at least according to Android expert Mishaal Rahman.
Rahman says that the Android 15 audio-sharing feature won’t be available on the Pixel 8a or older Pixel phones. Curiously, the Pixel 8a supports Bluetooth LE Audio, but it seems Google isn’t planning on “enabling the requisite broadcasting rules”.
Nothing is lost yet, though: Android 15 isn’t in its final version, so the devices may gain support for the feature. Nothing is certain as of now. In my opinion, if the hardware supports it – you should be able to have it. I personally dislike when manufacturers limit features despite hardware supporting them, just so more premium phones get to have an edge. But to be honest, I’m skeptical that the Pixel 8a won’t support it. I’d rather think it may gain support for the feature but at a later time.